Re: [Xen-devel] Segmentation fault of gdbserver-xen

[Akio Takebe <takebe_akio@xxxxxxxxxxxxxx>]

Hi, Kip

Thanks.
I can see the core.
xc_waitdomain_core() don't supported x86_64.
I'll send a patch to fix the issue.


#gdb tools/debugger/gdb/gdb-6.2.1-linux-i386-xen/gdb/gdbserver/gdbserver-xen 
./core.7633

(gdb) bt
#0  0x00002ab2a8478f7b in xc_waitdomain_core () from 
/usr/lib64/libxenctrl.so.3.0
#1  0x00002ab2a8478afb in xc_waitdomain () from /usr/lib64/libxenctrl.so.3.0
#2  0x0000000000404e10 in linux_wait (status=0x7fffff7fe6c7 "") at 
../../../gdb-6.2.1/gdb/gdbserver/linux-xen-low.c:229
#3  0x0000000000404391 in mywait (statusp=Variable "statusp" is not available.
) at ../../../gdb-6.2.1/gdb/gdbserver/target.c:99
#4  0x0000000000403cd4 in main (argc=4, argv=0x7fffff7fef18) at 
../../../gdb-6.2.1/gdb/gdbserver/server.c:84
(gdb) x/16i 0x00002ab2a8478f60
0x2ab2a8478f60 <xc_waitdomain_core+352>:        mov    %ebx,%es
0x2ab2a8478f62 <xc_waitdomain_core+354>:        (bad)  
0x2ab2a8478f63 <xc_waitdomain_core+355>:        (bad)  
0x2ab2a8478f64 <xc_waitdomain_core+356>:        pushq  (%rcx)
0x2ab2a8478f66 <xc_waitdomain_core+358>:        leaveq 
0x2ab2a8478f67 <xc_waitdomain_core+359>:        mov    1225914(%rip),%rax       
 # 0x2ab2a85a4428 <p2m_array>
0x2ab2a8478f6e <xc_waitdomain_core+366>:        inc    %esi
0x2ab2a8478f70 <xc_waitdomain_core+368>:        mov    (%rax,%rcx,8),%rdx
0x2ab2a8478f74 <xc_waitdomain_core+372>:        mov    1225893(%rip),%rax       
 # 0x2ab2a85a4420 <m2p_array>
0x2ab2a8478f7b <xc_waitdomain_core+379>:        mov    %rcx,(%rax,%rdx,8)
0x2ab2a8478f7f <xc_waitdomain_core+383>:        movslq %esi,%rcx
0x2ab2a8478f82 <xc_waitdomain_core+386>:        cmp    1225895(%rip),%rcx       
 # 0x2ab2a85a4430 <nr_pages>
0x2ab2a8478f89 <xc_waitdomain_core+393>:        jl     0x2ab2a8478f67 
<xc_waitdomain_core+359>
0x2ab2a8478f8b <xc_waitdomain_core+395>:        jmpq   0x2ab2a8478e28 
<xc_waitdomain_core+40>
0x2ab2a8478f90 <xc_waitdomain_core+400>:        lea    4785(%rip),%rdi        # 
0x2ab2a847a248
0x2ab2a8478f97 <xc_waitdomain_core+407>:        mov    $0xf00febed,%edx

Best Regards,

Akio Takebe

>You will need to re-compile and re-install libxenctl with symbols (add
>-g to the Makefile). With that done you'll be able to see where the
>segmentation fault is occurring. There are frequently problems in the
>domain VA mapping function.
>
>                          -Kip
>
>On Thu, 24 Aug 2006, Akio Takebe wrote:
>
>> Hi,
>>
>> I tried to run gdbserver-xen with --file on xen-x86_64.
>> But I have the following fault.
>> Do anyone have the same error?
>> Or do I have mistakes?
>>
>> # gdbserver-xen 127.0.0.1:9999 --file /var/xen/dump/vm1.1.core
>> Attached; pid = 3
>> Segmentation fault
>>
>> A part of the strace is below.
>>
>> mmap(NULL, 1264480, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
>> 0) = 0x2b01270d9000
>> mprotect(0x2b01270e5000, 1215328, PROT_NONE) = 0
>> mmap(0x2b01271e4000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|
>> MAP_DENYWRITE, 3, 0xb000) = 0x2b01271e4000
>> mmap(0x2b01271e5000, 166752, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED
>> |MAP_ANONYMOUS, -1, 0) = 0x2b01271e5000
>> close(3)                                = 0
>> open("/lib64/tls/libc.so.6", O_RDONLY)  = -1 ENOENT (No such file or
>> directory)
>> open("/lib64/libc.so.6", O_RDONLY)      = 3
>> read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\300\313"...,
>> 640) = 640
>> fstat(3, {st_mode=S_IFREG|0755, st_size=1485035, ...}) = 0
>> mmap(0x386c200000, 2303368, PROT_READ|PROT_EXEC, MAP_PRIVATE|
>> MAP_DENYWRITE, 3, 0) = 0x386c200000
>> mprotect(0x386c329000, 1086856, PROT_NONE) = 0
>> mmap(0x386c428000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|
>> MAP_DENYWRITE, 3, 0x128000) = 0x386c428000
>> mmap(0x386c42e000, 17800, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|
>> MAP_ANONYMOUS, -1, 0) = 0x386c42e000
>> close(3)                                = 0
>> mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
>> = 0x2b012720e000
>> mprotect(0x386c428000, 12288, PROT_READ) = 0
>> munmap(0x2b01270b3000, 154694)          = 0
>> open("2006-0823-1442.14-vm1.1.core", O_RDONLY) = 3
>> open("/proc/xen/privcmd", O_RDWR)       = 4
>> fcntl(4, F_GETFD)                       = 0
>> fcntl(4, F_SETFD, FD_CLOEXEC)           = 0
>> brk(0)                                  = 0x50d000
>> brk(0x52e000)                           = 0x52e000
>> rt_sigaction(SIGRT_1, {SIG_IGN}, {SIG_DFL}, 8) = 0
>> write(2, "Attached; pid = 3\n", 18)     = 18
>> read(3, "\355\353\17\360\1\0\0\0\355\371\0\0\30\0\0\0H\24\0\0\0"..., 24)
>> = 24
>> read(3, "\177\3\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\200"...,
>> 5168) = 5168
>> mmap(NULL, 512000, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
>> 0) = 0x2b012720f000
>> read(3, "\2520\20\0\0\0\0\0:9\20\0\0\0\0\0\2764\20\0\0\0\0\0\333"...,
>> 511848) = 511848
>> mmap(NULL, 8392704, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
>> 0) = 0x2b012728c000
>> --- SIGSEGV (Segmentation fault) @ 0 (0) ---
>> +++ killed by SIGSEGV +++
>>
>> Best Regards,
>>
>> Akio Takebe
>>
>>
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>> http://lists.xensource.com/xen-devel
>>


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